Energy used in the world can be derived from the combustion of carbon and hydrogen-containing fuels such as coal, oil, peat, waste and natural gas. In addition to carbon and hydrogen, these fuels contain oxygen, moisture and contaminants. The combustion of such fuels results in the production of a gas stream containing the contaminants in the form of ash, carbon dioxide (CO2), sulfur compounds (often in the form of sulfur oxides, referred to as “SOx”), nitrogen compounds (often in the form of nitrogen oxides, referred to as “NOx”), chlorine, mercury, and other trace elements. Awareness regarding the damaging effects of the contaminants released during combustion triggers the enforcement of even more stringent limits on emissions from power plants, refineries and other industrial processes. There is an increased pressure on operators of such plants to achieve near zero emission of contaminants. However, removal of contaminants from the gas stream, such as a flue gas stream, requires a significant amount of energy.
Moreover in CAP processing the CAP stripper functions to separate a water/ammonia/CO2 solution absorbed in the water wash column. The ammonia is returned to the CO2 absorber for capture of CO2, and water is returned to the water wash column for ammonia capture. To strip ammonia from the ammonia rich water wash solution, steam is provide to a heat exchanger or reboiler to heat the fluid flowing through the ammonia stripper. As known, a reduction in the use of steam for such a system with no penalty is advantageous to the efficiency of the system.
Accordingly, there exists a need for the reduction of the use of steam in such systems and processes for recovering ammonia and carbon dioxide from a flue gas stream in carbon capture system, particularly in CAP applications.